Compact optics for concentration, aggregation and illumination of light energy

ABSTRACT

A solar concentrator having a concentrator element for collecting input light, a redirecting component with a plurality of incremental steps for receiving the light and also for redirecting the light, and a waveguide including a plurality of incremental portions enabling collection and concentration of the light onto a receiver. Other systems replace the receiver by a light source so system optics can provide illumination.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is continuation application and claims priority to U.S.patent application Ser. No. 12/207,346 now U.S. Pat. No. 7,664,350,filed Sep. 9, 2008, which claims priority to U.S. patent applicationSer. No. 11/852,854 now U.S. Pat. No. 7,672,549, filed Sep. 10, 2007,incorporated herein by reference in its entirety.

This invention is directed to a solar concentrator for producingelectrical, thermal and radiative energy. More particularly, theinvention is directed to a solar concentrator using a combination ofrefractive and reflective and/or redirecting optics to concentrate andaggregate sunlight from a plurality of concentrator systems. Otherapplications include lighting and illumination using the compact optics.

BACKGROUND OF THE INVENTION

Solar collectors have long been developed for the collection andconcentration of sunlight. Increasing the energy density of ambientsunlight enables more efficient conversion to useful forms of energy.Numerous geometries and systems have been developed, but the mediocreperformance and high costs of such systems do not permit widespread use.In order to achieve adequate performance and manufacturability,improvements in solar energy collectors are needed.

SUMMARY OF THE INVENTION

A concentrator system includes a combination of optical elementscomprising a concentrating element, such as a refractive and/orreflective component, a reflective and/or refractive element to redirectsunlight into a light waveguide which is constructed with a plurality ofstepped reflective surfaces for efficient aggregation and concentrationinto a receiver unit (thermal and/or photovoltaic) and otherconventional energy conversion systems. The control of the geometry ofthe reflective surfaces along with the aspect ratio of the lightwaveguide enables ready manipulation, collection and concentration ofsunlight preferably onto a contiguous area for a variety of commercialapplications, including solar cell devices, light pipe applications,heat exchangers, fuel production systems, spectrum splitters and othersecondary manipulation of the light for various optical applications.

These and other objects, advantages and applications of the invention,together with the organization and manner of operation thereof, willbecome apparent from the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a solar energy concentrator generally constructed inaccordance with an embodiment of the invention;

FIG. 2 illustrates a cross-sectional view of one embodiment of a lightwaveguide shown schematically in FIG. 1;

FIG. 3 illustrates another cross-sectional view of a linear embodimentof a light waveguide shown schematically in FIG. 1;

FIG. 4 illustrates another cross-sectional view of a rotationalembodiment of a light waveguide shown schematically in FIG. 1;

FIG. 5A shows a first edge shape of a reflecting element of a waveguide;FIG. 5B shows a second edge shape for a reflecting element of awaveguide; FIG. 5C shows a first separate element for redirecting lightas part of a stepped waveguide; FIG. 5D shows a second separate elementfor redirecting light as part of a stepped waveguide; FIG. 5E shows asystem with plural light pipes coupled to a stepped waveguide and FIG.5F shows a waveguide with embedded redirecting components;

FIG. 6 shows a curved concentrating element and curved reflector coupledto a waveguide;

FIG. 7 shows a curved concentrating element and two planar reflectorscoupled to a waveguide;

FIG. 8A shows a closed optical element coupled to a waveguide and FIG.8B shows an enlarged view of a portion of FIG. 8A at the juncture of theoptical element and waveguide;

FIG. 9A shows another closed optical element coupled to a waveguide andFIG. 9B shows an enlarged view of a portion of FIG. 9A at the junctureof the optical element and the waveguide;

FIG. 10A shows another closed optical element coupled to a waveguide andFIG. 10B shows an enlarged view of a portion of FIG. 10A at a junctureof the optical element and the waveguide;

FIG. 11A shows a further closed element coupled to a waveguide and FIG.11B shows an enlarged view of portion of FIG. 11A at a juncture of theoptical element and the waveguide; and

FIG. 12 shows ray tracing results for the optical systems of FIGS. 2 and6-11.

FIG. 13 illustrates another representation of an embodiment of a solarenergy concentrator or an illuminator;

FIG. 14 illustrates a refractive concentrator component for aconventional system;

FIG. 15 illustrates a reflective concentrator component for anotherconventional system;

FIG. 16 illustrates a Cassegrainian concentrator having a primary andsecondary reflective optic;

FIG. 17 illustrates light transmission versus acceptance angle for asystem like FIG. 13.

FIG. 18 illustrates an embodiment where the waveguide ends with areflector component for redirecting light towards a base surface;

FIG. 19 illustrates a variation on FIG. 18 where the concentrator ismirrored about an axis of symmetry;

FIG. 20 illustrates a form of the embodiment of FIG. 13 with thewaveguide and redirecting elements tilted relative to the concentrators;

FIG. 21 illustrates an embodiment with varying size of concentratorand/or redirecting element;

FIG. 22 illustrates an embodiment for light diffusion using a lightsource in place of a receiver;

FIG. 23 illustrates a different variation on the embodiment of FIG. 4 toachieve light concentration across two axes;

FIG. 24 illustrates yet another embodiment to achieve concentrationacross two axes;

FIG. 25 illustrates a different embodiment of a solar concentrator ofthe invention;

FIG. 26 illustrates yet another embodiment of a solar concentrator ofthe invention;

FIG. 27 illustrates a further embodiment of a solar concentrator of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A solar energy concentrator system constructed in accordance with apreferred embodiment of the invention is indicated schematically at 10in FIG. 1. The solar energy concentrator system 10, includes an opticalconcentrating element 12 which can be any conventional opticalconcentrator, such as an objective lens, a Fresnel lens, and/or areflective surface element, such as a parabolic or compound shapedreflector. This optical concentrating element 12 acts on input light 14to concentrate the light 14 to a small focal area 16. In the preferredembodiment, the small focal area 16 is disposed within reflective orredirecting component 18, or other conventional optical redirectingelement which causes total internal reflection. The redirectingcomponent 18 redirects the concentrated light 20 into a waveguide 22.The waveguide 22 is constructed to cause internal reflection of thelight 20 which propagates along the waveguide 22 in accordance withSnell's law wherein total internal reflection occurs when the angle ofthe light 20 incident on surface 24 of the waveguide 22 is greater thanthe critical angle, Ø_(c):Ø_(c)=sin(η_(waveguide)/η_(cladding))

Where Ø_(c)=critical angle for total internal reflection,

η_(waveguide)=refractive index of waveguide material

η_(cladding)=refractive index of a cladding layer or the index at theambient/waveguide interface.

A receiver 26 is disposed at the end of the waveguide 22 and receivesthe light 20 for processing into useful energy or other opticalapplications.

FIG. 13 illustrates a preferred form of the system 10 with details ofthis mechanism. A plurality N of concentrating elements 12 andredirecting elements 18 are shown. Each of the concentrating elements 12takes the input light 14 with a half angle of θ₁ from an area A, andconcentrates the light 14 to a smaller area B with half angle θ₂, suchthat Concentration Ratio=A/B. Each of the redirecting elements 18receives the concentrated light from an associated one of theconcentrating elements 12, rotates it by some angle φ, and inserts itinto a section of the waveguide 22, preserving the level ofconcentration defined by area B and half angle θ₂. The waveguide 22 is aplurality of sections having incremental steps of height B that arespaced from each other by length A. Each section of the waveguide 22receives light from an associated one of the redirecting elements 18,such that the waveguide 22 as a whole aggregates light from theplurality of the concentrating elements 14 and the redirecting elements18, and propagates the light 14 along its length for collection by areceiver 23. The waveguide 22 does not change the level of concentrationdelivered to it, and therefore the aspect ratio of the waveguide 22

  = height  of  waveguide/length  of  waveguide  = N × B/N × A  = B/A  = 1/Concentration  Ratio  in  each  element

Compactness has great practical benefits for solar concentrators (andother devices such as illuminators). Among other benefits: less materialis used, large air gaps between optics and the receiver 23 that needdifficult sealing are eliminated, devices are much less bulky forcheaper shipping and installation, traditional flat module manufacturingmethods can be utilized as opposed to expensive and risky custommanufacturing methods.

The limit of compactness for the waveguide 22 is defined by the receiver23. Thus, the waveguide 22 can only be as compact as the receiver 23 towhich it delivers light. For most concentrators, the compactness of theconcentrator 12 is significantly larger than the width of the receiver23. However, since this device constructs the waveguide 22 from sectionseach having height defined by the area of concentrated light deliveredto it, the aggregated waveguide 22 has a height equal to the width ofthe receiver 23. In other words, the waveguide 22 is at the limit, ofcompactness.

Therefore in view of the construction of the invention, theconcentration of light achieved by the concentrator system 10 being afunction of the aspect ratio A/B leads to a highly compact concentratorsystem 10. The device can aggregate light from a relatively wide areaand concentrate it to a relatively small receiver that has a contiguousarea while remaining highly compact. This simplifies production byreducing the volume of material required, allowing for multiple units tobe made from a single mold and reducing assembly complexity.

FIG. 12 shows the results of ray tracings performed on the designsdepicted in FIGS. 2 and 6-11. Each design demonstrates a particularperformance in terms of its ability to concentrate light in the lineardimension, as shown by the ratio of A/B. The data is for light having aninput cone half angle of +−1 degree, an output cone half angle of +−20degrees, an initial refractive index of n=1, and a final refractiveindex of n=1.5. The theoretical maximum allowable concentration of lightwith those input parameters is 30× in the linear dimension, whereas FIG.9 for example achieves a concentration factor of 25×. Since theconcentration factor in the linear dimension is proportional to theaspect ratio A/B, the design shown in FIG. 9 can deliver a concentratorthat is 250 millimeters long (A) while only 10 millimeters in thickness(B); or a concentrator that is 500 millimeters long (A) while only 20millimeters in thickness (B). This represents a highly compactconcentrator system 10 that can effectively aggregate concentrated lightfrom a relatively wide area and deliver it to a single receiver.

The dimensions and number of the concentrating elements 12 andredirecting elements 18 can be varied for any entry aperture of theconcentrator 12. For example, the system 10 shown in FIG. 13 can beachieved with twice as many elements (2×N) of half the size (A/2 andB/2). As the concentrating elements 12 and the redirecting elements 18become smaller and more numerous; the aspect ratio of the entireconcentrator 12 approaches the aspect ratio of the waveguide 22, givenby 1/Concentration Ratio. In other words, for a Concentration Ratio of10, the aspect ratio of the concentrator 12 can be 0.1.

Typical aspect ratios for concentrators 12 are on the order of 1. FIG.14 shows a refractive concentrator 12, which may be, for example, anobjective lens or a Fresnel lens. The focal length of an objective lensdefines the height 25. The Concentration Ratio is given by A/B, whereasthe aspect ratio is given by height/A, which is larger than theConcentration Ratio. FIG. 15 shows a similar situation for a reflectiveform of the concentrator 12.

Attempts have been made to reach the limit of compactness for a singleconcentrating element. FIG. 16 shows a Cassegrainian concentratorcomposed of a primary and secondary reflective optic. The aspect ratiogiven by Height/A is 0.25. Winston, in “Planar Concentrators Near theEtendue Limit”, 2005, describes the “fundamental compactness limit of a¼ aspect ratio.” In the context of the invention, this compactness limitapplies to an individual one of the concentrating elements 12. The useof the waveguide 22 that aggregates light from multiple ones of theconcentrating elements 12 is what allows the compactness of the system10 to go lower than ¼ and approach 1/Concentration Ratio.

The invention also has advantages in the transmission efficiency oflight energy from input to delivery to the receiver 23. In FIG. 13, θ₂is controlled by the concentrating element 12. θ₂ also becomes the anglemade by the light hitting the surface of the waveguide 22, and 90-θ₂ isthe angle made with respect to the normal of the waveguide surface. Asdiscussed above, θ₂ can be set to achieve total internal reflectionwithin the waveguide 22, reducing surface absorption losses to zero.

In addition, the concentrating element 12 and redirecting element 18 canbe designed to manipulate the light 14 using total internal reflection,as shown in specific embodiments below. Also, the concentrating element12 and redirecting element 18 and the waveguide 22 can be designed toprovide a contiguous path within a solid dielectric medium for the light14. In other words, light rays from the input region to the receiver 23need never encounter either a reflective coating or a change inrefractive index. Reflective coatings can cause absorption losses of˜8%. A change in refractive index from an optical material of refractiveindex 1.5 (plastic or glass) to air can cause Fresnel reflection lossesof ˜4%. Transmission efficiency with respect to these loss mechanismscan therefore approach 100%.

This is in contrast to conventional concentrator optics. Reflectiveoptics will have 8% loss per reflection. Transmission efficiency willtherefore be ˜92% for a single optic, and ˜85% when a secondaryreflective optic is used. Refractive optics require at least one changein refractive index. Transmission efficiency will therefore be ˜96% fora single optic, and ˜92% when a secondary refractive optic is used.

FIG. 17 shows transmission as a function of input half angle θ₁ throughthe embodiment of the invention shown in FIG. 13. The calculation isbased on ray tracing software. The embodiment was designed to functionwithin input angles of +−3 degrees. The efficiency takes into accountlosses from Fresnel reflections and hard reflections. As is shown, theefficiency of the device approaches 100% at θ₁=0 degrees, stays near100% within +−3 degrees, and then drops off sharply.

In another preferred form of the concentrator system 10 shown in FIG. 2,the incident light 14 is concentrated or focused in a first step usingthe element 12 described hereinbefore. The concentrated light 20 isfurther processed by associating sections of the concentrator system 10with reflector/waveguide sections 28. Each of the reflector/waveguidesections 28 comprises a reflective section 32 which receives theconcentrated light 20 and redirects light 30 within the associatedwaveguide section 28 with the light 30 undergoing total internalreflection (TIR) along the length of the entire waveguide 22. Aplurality of the reflector/waveguide sections 28 comprise the waveguide22 and forms a stepped form of waveguide construction.

FIG. 18 shows another embodiment of the system 10 where the waveguide 22ends in a reflector 27 that redirects the light 14 towards the basesurface of the waveguide 22, where the receiver 23 may be placed. It canbe of manufacturing benefit to have the concentrator optics be laid downflat onto a plane of conventional receiver elements which embody thereceiver 23.

With this construction, the concentrator 12 can be mirrored about anaxis of symmetry as shown in FIG. 19, such that the two receivers 23from either end form one contiguous area where one single receiver 23may be placed. In this case, since the aperture area is doubled but thethickness of the concentrator 12 unchanged, the limit of compactness isgiven by 1/(2× Concentration Ratio).

The redirecting element 18 rotates the light paths by an angle φ. InFIG. 13, φ is shown to be 90 degrees. FIG. 20 depicts y<90 degrees. Thiscan allow, as one benefit, the concentrating elements 12 to be locatedon the same plane, and the redirecting elements 18 on their own plane aswell, which can aid manufacturability.

The concentrating element 12 and the redirecting element 18, andassociated waveguides 22, may also vary in size and FIG. 21 shows anexample of this. Here A1, A2, and A3 are different lengths, as are B1,B2 and B3. However, the Concentration Ratio stays the same in eachsection: A1/B1=A2/B2, and so on. The aspect ratio of the waveguide 22 istherefore still given by

  = (B 1 + B 2 + B 3)/(A 1 + A 2 + A 3)  = 1/Concentration  Ratio

In another embodiment shown in FIG. 22, the system 10 can also beutilized as a light diffuser by running light 31 through it in reverse.In FIG. 22, light input from a light source 33 that was originally thereceiver 23, is channeled through the waveguide 22, redirected by theredirecting element 18 onto the concentrating element 12, which deliversthe output light above the system 10. Applications include illumination,backlighting, and other light diffusing devices. It should be understoodthroughout that optics illustrated for concentration of light can alsobe used for illumination with the “receiver 23” being replaced by alight source.

The cross-section of the various reflector/waveguide sections 28provides a basic building block for various configurations of theconcentrator system 10. One exemplary commercial embodiment is shown inFIG. 3 with an aspect ratio N×B/N×A, A/B, an area concentration factoror energy density ΔØ which is proportional to A/B where N×A is thelength of the waveguide 22 and N×B is the largest thickness (see FIGS. 2and 3). In a most preferred embodiment, the thickness N×B is comprisedof a plurality of incremental step heights, B, which provide a clearlight pathway for TIR light from each of the reflector/waveguidesections 32.

FIG. 4 illustrates another example of the concentrator system 10 in theform of a rotationally (or axially) symmetric geometry having aconcentrator system 10′ and the concentrating element 12 in associationwith the reflector/waveguide sections 28 of the waveguide 22. Thisrotationally symmetric form of the concentrator system 10′ (or thesystem 10), which can be any portion of a full circle, enables threedimensional radial convergence of the incident light 14 resulting in ΔØthe Concentration Ratio being proportional to (A/B)² therebysubstantially enhancing collection and concentrator efficiency. In amost preferable embodiment of FIG. 4 two axis solar tracking is used asopposed to the single axis tracking for the embodiment of FIG. 3.

FIG. 4 shows one way to achieve concentration across two axes, and FIG.23 shows another way. Here, a linearly symmetric primary concentrator 12delivers light concentrated along one axis to its receiver 23 at theside of a concentrator 12. There, a second linearly symmetricconcentrator 37 is positioned in the perpendicular axis. This secondaryconcentrator 37 concentrates light along the second axis, bringing thelight to the final receiver 23.

FIG. 24 shows a third way to achieve concentration across two axes. Herethe concentrators 12 shown are of the mirror symmetry as described inFIG. 19. Again, a linearly symmetric primary concentrator 12 deliverslight 14 concentrated along one axis to its receiver 23 at the base ofthe concentrator 12. There, a second linearly symmetric concentrator 37is positioned in the perpendicular axis. This secondary concentrator 37concentrates the light 14 along the second axis, bringing the light tothe final receiver 23.

In addition to the linear and rotational embodiments of FIGS. 3 and 4,the concentrator system 10′ can be disposed both above and/or below thewaveguide 22 relative to the direction of the incident light 14. In suchembodiments, some of the light 14 will pass through the waveguide 22 andbe redirected back to the waveguide 22 by the concentrator system 10′.These forms of systems enable light recycling and thus improve endefficiency and the use of the reflective systems for concentration,described herein, show an increased efficiency for concentration oflight relative to conventional refractive system.

In other embodiments, the reflective elements 18 can be angularlyadjusted with respect to the waveguide 22 in order to cause TIR. Thereflective element 18 can be an integral part of the waveguide 22 with avariety of angular profiles (see FIGS. 5A and 5B). The element 18 alsocan be separate elements 38 and 39 (see FIGS. 5C and 5D). In addition,the reflective element 18 and the associated waveguide 22 can also takethe form of complex light collector pipes 42 and light redirectingcomponents 43 as shown in FIGS. 5E and 5F, respectively.

The above described forms of the concentrator system 10 and 10′ provideconcentrated light 20 to a contiguous area as opposed to a nodal area,thereby allowing delivery of concentrated solar energy to a variety ofdownstream receivers 26, such as a solar cell, a light pipe for furtherprocessing, a heat exchanger, a secondary concentrator and a lightspectrum splitter.

In yet another series of embodiments shown in FIGS. 6-11B, a variety ofoptical components can be used in combination to further andsubstantially enhance both the concentration and collection efficiency.FIG. 6 in a most preferred embodiment shows a curved concentratingelement 50 directing light 52 onto a curved reflector 54 which passesthe light 52 into the waveguide 22. FIG. 7 in another most preferredembodiment shows another curved concentrating element 56 which directsthe light 52 off a reflector 58 having two planar surfaces 59 and 60which redirect the light 52 by TIR into the waveguide 22. FIG. 8A showsa partially closed optical element 64 which redirects the light 52 atinterface 66, reflects the light 52 off curved reflector 68 focusing thelight 52 onto interface 70 between a bottom reflective surface 72 of theoptical element 64. As best seen in the enlarged view of FIG. 8B, thewaveguide 22 has a substantially complementary angular match to thereflective surface 72.

In FIG. 9A in another most preferred embodiment is a similar system asin FIG. 8A, but the optical element 65 is closed and coupled to anextension waveguide 74 (a form of light pipe) which collects the light52 and transmits it into the waveguide 22 (as best seen in FIG. 9B).

In FIG. 10A an optical element 76 is closed with the input light 52reflected by TIR from reflective surface 77 with a particular angularcross section best shown in FIG. 10B which enables collection of thelight from TIR and coupling with the waveguide 22 from reflection offsurfaces 80, 81 and 82.

In FIG. 11A an optical element 82 cooperates with another reflector 84to direct the light 52 into the waveguide 22 from the two differentoptical sources 82 and 84, thereby further ensuring collection of allthe light incident on surface 86 of the optical element 82. In thisembodiment the optical elements 82 and 84 perform the role of bothconcentrating elements and reflecting elements.

In FIG. 25, a curved concentrating element 12 directs the light 14 onto(the redirecting component 18) which passes the light 14 into thewaveguide 22. The concentrating element 12 and the redirecting component18 are shown as two different features on the same physical part, whilethe waveguide 22 is shown as a second physical part coupled to thefirst. In FIG. 26, a curved concentrating element 12 directs the light14 onto two reflectors (the redirecting component 18) acting in sequencewhich pass the light 14 into the waveguide 22. The concentrating element12, the redirecting component 18, and waveguide 22 are all shown asseparate physical parts coupled together. FIG. 27 directs the light 14into the waveguide 22 similar to FIG. 26. However, the redirectingcomponent 18 and the waveguide 22 are combined into one construction.

The foregoing description of embodiments of the present invention hasbeen presented for purposes of illustration and description. It is notintended to be exhaustive or to limit the present invention to theprecise form disclosed, and modifications and variations are possible inlight of the above teachings or may be acquired from practice of thepresent invention. The embodiments were chosen and described in order toexplain the principles of the present invention and its practicalapplication to enable one skilled in the art to utilize the presentinvention in various embodiments, and with various modifications, as aresuited to the particular use contemplated.

1. An optical concentrator, comprising: a plurality of optical elementsdisposed adjacent each other with each of the plurality of opticalelements including: a) a concentrating element for collecting andrepositioning light; and b) an associated redirecting element which isoptically associated with and physically separate from the concentratingelement for receiving light from the concentrating element, wherein theconcentrating element of each of the plurality of optical elements isseparated from at least one portion of the associated redirectingelement by a layer within which the light does not undergo arepositioning change of direction, and the layer being contiguousbetween at least a portion of each of the associated redirectingelements; the optical concentrator further including a stepped waveguidefor receiving the light from the at least one portion of the associatedredirecting element which is constructed to reposition the light intothe stepped waveguide for accumulation, the waveguide aggregating thelight from the plurality of optical elements to provide opticalconcentration of the light for use thereof.
 2. The optical concentratoras defined in claim 1 wherein the plurality of optical elements and thestepped waveguide each form a contiguous layer and are disposed in astack of physically separate components, thereby enabling directassembly of separate parts comprising the optical concentrator.
 3. Theoptical concentrator as defined in claim 1 wherein the waveguideincludes an upper and a lower element which are substantially parallel.4. The optical concentrator as defined in claim 1 wherein the opticalelements are selected from the group consisting of a parabolic surface,an elliptical surface, a hyperbolic surface, an arc, a flat reflectivesurface, a tailored shape reflective surface, a total internalreflecting surface, a compound parabolic concentrator optic, arefractive component selected from the group of a spherical component,an aspherical component, a Fresnel lens, a cylindrical lens and atailored shape.
 5. The optical concentrator as defined in claim 1wherein the optical concentrator is linearly symmetric.
 6. The opticalconcentrator as defined in claim 1 wherein the optical concentrator isrotationally symmetric.
 7. The optical concentrator as defined in claim1 wherein the optical concentrator further includes a receiver whichcollects the aggregated light for use thereof.
 8. The opticalconcentrator as defined in claim 1 wherein the concentrating element iscomprised of a combination of (1) a surface between a high indexmaterial and a low index material enabling refraction of input light and(2) a parabolic reflective surface which repositions the input lightwith the combination outputting the input light without the input lightbeing repositioned more than once by the parabolic reflective surface.9. The optical concentrator as defined in claim 1 wherein an end of thestepped waveguide comprises additional optical features that redirectthe light from the waveguide towards a receiver.
 10. The opticalconcentrator as defined in claim 1 where the plurality of opticalelements and the stepped waveguide are mirrored about a central axis toform at least two systems, such that a receiver in each of the at leasttwo systems combine to form one contiguous receiver, and the opticalconcentrator comprises an increased width of at least about twice thatof one system while retaining a same height.
 11. The opticalconcentrator as defined in claim 1 wherein the concentrating element andthe redirecting element have a size selected from the group of about thesame size and varying size.
 12. A optical concentrator, comprising: aplurality of optical elements disposed adjacent each other with each ofthe plurality of optical elements including a concentrator element forcollecting and repositioning input light; and the optical concentratorfurther including: a waveguide comprised of a plurality of portions witheach of the portions associated with one of the concentrating elements,each of the waveguide portions further having a feature associated withreceiving the output light from the concentrating element, the waveguideaggregating the light from the plurality of optical elements; whereinthe plurality of optical elements and the waveguide each form contiguoushorizontal layers disposed in a vertical stack.
 13. An optical systemfor processing light from a light source to provide illumination output,comprising: a stepped waveguide for collecting input light from a lightsource and delivering the input light to step features of the steppedwaveguide; a plurality of optical elements disposed adjacent each otherwith each of the plurality of optical elements including: a) aredirecting element for receiving the input light from the steppedwaveguide and repositioning the input light; b) an associatedconcentrating element which is associated with and separate from theredirecting element for receiving light from the redirecting element anddiffusing the light for output therefrom to provide the illuminationoutput, wherein the concentrating element of each of the plurality ofoptical elements is separated from at least one portion of theassociated redirecting element by a layer within which the light doesnot undergo a repositioning change of direction and the layer beingcontiguous between at least a portion of each of the associatedredirecting elements.
 14. An optical concentrator, comprising: aplurality of optical elements disposed adjacent each other with each ofthe plurality of optical elements including: a) a refractingconcentrator element for collecting and repositioning light; and b) anassociated redirecting element which is associated with and separatefrom the concentrating element for receiving the light from theconcentrating element wherein the concentrating element of each of theplurality of optical elements is separated from at least one portion ofthe associated redirecting element by a layer within which the lightdoes not undergo a repositioning change of direction and the layer beingcontiguous between at least a portion of each of the optical elements;and the optical concentrator further including: a waveguide forreceiving the light from the at least one portion of the associatedredirecting element which is constructed to reposition the light intothe waveguide for accumulation, the redirecting element being anintegral part of the waveguide, the waveguide having top and bottomsurfaces that are substantially parallel, the waveguide having asubstantially uniform thickness along its length, and the opticalelements constructed so as to insert the light into the waveguide suchthat light is propagated multi-directionally within the waveguide. 15.An optical concentrator, comprising: a plurality of optical elementsdisposed adjacent each other with each of the plurality of opticalelements including: a) a refracting concentrator element for collectingand repositioning light; and b) an associated redirecting element whichis associated with and separate from the concentrating element forreceiving light from the concentrating element wherein the concentratingelement of each of the plurality of optical elements is separated fromat least one portion of the associated redirecting element by a layerwithin which the light does not undergo a repositioning change ofdirection and the layer being contiguous between at least a portion ofeach of the associated redirecting elements; and the opticalconcentrator further including: a stepped waveguide for receiving thelight from the at least one portion of the associated redirectingelement which is constructed to reposition the light into the steppedwaveguide for accumulation; and an additional optical element coupled tothe stepped waveguide that redirects the light from the waveguidetowards a light receiver.
 16. An optical concentrator, comprising: aplurality of optical elements disposed adjacent each other with each ofthe plurality of optical elements including: a) a concentrating elementfor collecting and repositioning light; and b) an associated redirectingelement which is associated with and separate from the concentratingelement for receiving light from the concentrating element, wherein theconcentrating element of each of the plurality of optical elements isseparated from at least one portion of the associated redirectingelement by a layer within which the light does not undergo arepositioning change of direction, and the layer being contiguousbetween at least a portion of each of the associated redirectingelements; the optical concentrator further including a stepped waveguidefor receiving the light from the at least one portion of the associatedredirecting element which is constructed to reposition the light intothe stepped waveguide for accumulation; the above elements beingconstructed in a cross-section, the cross-section then being extruded toform the optical concentrator.
 17. An optical concentrator, comprising:a plurality of optical elements disposed adjacent each other with eachof the plurality of optical elements including: a) a concentratingelement for collecting and repositioning light, wherein the light isrepositioned along one axis of the concentrating element; and b) anassociated redirecting element which is associated with and separatefrom the concentrating element for receiving light from theconcentrating element, wherein the concentrating element of each of theplurality of optical elements is separated from at least one portion ofthe associated redirecting element by a layer within which the lightdoes not undergo a repositioning change of direction, and the layerbeing contiguous between at least a portion of each of the associatedredirecting elements the optical concentrator further including astepped waveguide for receiving the light from the at least one portionof the associated redirecting element which is constructed to repositionthe light into the stepped waveguide for accumulation.